Summary & Overview
CPT 84182: Western Blot Protein Fraction Analysis
CPT code 84182 denotes a Western blot laboratory test used to separate and evaluate protein fractions in blood or other body fluids. This specialized immunoblotting procedure plays a key role in confirming the presence, absence, or quantity of targeted proteins — information that can be critical for diagnosis, monitoring, and guiding treatment in infectious disease, autoimmune, and other clinical contexts. Nationally, accurate coding and billing for such specialized laboratory services affect clinical reporting, reimbursement, and laboratory operations.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context and typical sites of service, plus coverage and billing considerations relevant to major national payers. The publication summarizes common modifiers used with laboratory services, notes where input data is unavailable, and outlines what readers can expect regarding benchmarking, policy updates, and operational implications for laboratories that perform Western blot testing.
This analysis is intended for a national audience of laboratory managers, coding and billing specialists, and policy analysts seeking clarity on the clinical purpose of CPT code 84182, payer considerations, and the types of content covered in the full publication.
Billing Code Overview
CPT code 84182 describes a laboratory procedure in which a lab analyst separates and evaluates levels of specific protein fractions in a patient specimen using the Western blot technique. The service involves protein separation, transfer, and immunodetection steps to identify and quantify targeted proteins in blood or other body fluids.
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Service type: Laboratory diagnostic test — protein electrophoresis and immunoblotting
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Typical site of service: Clinical laboratory or hospital laboratory performing specialized serologic and protein analysis
Clinical & Coding Specifications
Clinical Context
A 38-year-old patient presents to the outpatient infectious disease clinic with signs of a chronic viral infection after a prior indeterminate serologic screen. The clinician orders a confirmatory Western blot to evaluate specific viral protein bands from a patient serum specimen. Blood is drawn in the clinic phlebotomy area, labeled, and routed to the hospital central laboratory. The laboratory technologist performs gel electrophoresis, transfers proteins to membrane, incubates with patient serum and labeled antibodies, and interprets the banding pattern. Results are reported to the ordering provider; a copy is placed in the electronic medical record and communicated to the patient during a follow-up visit or telephone encounter.
Typical site of service: outpatient laboratory or hospital clinical laboratory.
Typical service type: laboratory diagnostic test using Western blot technique for separation and immunodetection of protein fractions from blood or other body fluid.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation component by the pathologist or laboratory physician. |
TC |